The best free option covers both assistants, asks for almost no permissions, and toggles on a single keypress. Docognito is a free extension built to that exact checklist for both ChatGPT and Claude, with no account and no payment required. Check any alternative against those three points before you install it, not after.
What the extension is allowed to touch
A screen disguise sits directly on top of a page where you might paste something sensitive, so the honest first question is not how it looks but what it can see and do. Chrome shows the permissions an extension requests before you install it, and that list is the one claim in the whole listing you get to verify rather than take on faith. Read it before the screenshots.
That single habit filters out more bad options than any feature comparison does, because a permission request tells you what the extension is capable of regardless of what its description says.
A star rating does not tell you the same thing. Reviews on the Chrome Web Store measure whether an extension does what it claims, not whether what it claims is a reasonable amount of access to ask for in the first place. A well-reviewed extension can still request more than a screen disguise needs, and the rating will not warn you about that, because the people leaving it are judging a different question entirely.
The checklist worth running
| What to check | Why it matters | Where Docognito lands |
|---|---|---|
| Covers the assistant you use | A ChatGPT-only tool is no help if you also use Claude | Both claude.ai, chatgpt.com and chat.openai.com, and no other website |
| Permission list is short | Fewer permissions means less the extension is capable of, whether or not it uses them | one browser permission, storage |
| One keypress, no menu hunting | A disguise you cannot toggle in a second is not fast enough for the moment it is needed | Shift and Escape, which both hides the disguise and brings it back |
| No account, no payment | An account is one more place your usage is logged somewhere | free, with no account and no payment |
| Honest about what it does not cover | A tool that overclaims sets you up to be caught by the one thing it never actually hid | Does not claim to hide the address bar |
The row worth pausing on is the last one, because it is the one most listings skip.
Why coverage of both assistants is worth checking
If you only ever use one assistant, a single-site extension does the job fine. Plenty of people move between the two depending on the task, though, and a disguise tool that only recognises one of them means learning two different toggles, or worse, forgetting which tab has protection and which does not. A tool built for claude.ai, chatgpt.com and chat.openai.com, and no other website removes that decision, because the same keypress works regardless of which tab you are on.
The permission count is not a small detail
one browser permission, storage is not a marketing line, it is a technical fact about what the extension is built to do. An extension that also wants access to your browsing history, your bookmarks, or every website you visit is asking for capability well beyond redrawing one page, and that gap between what it needs and what it asks for is exactly what a short permissions list rules out. You do not have to trust a promise about restraint when the permission simply is not there to misuse.
What free actually means here
Docognito has no trial period and no ads anywhere in it, and that is worth checking rather than assuming, because plenty of tools marketed as free turn out to mean free to install and then paid to keep using, with a countdown running somewhere in the background. A paid competitor built the same way would need an account to check a subscription against and a licensing server to ask, and an extension whose only permission is one browser permission, storage has no route to build either without asking for more access than a page redraw needs. No trial and no ads follow from what the extension is built to do, not from a separate promise sitting on top of it.
What no extension on this list can do
the address bar, which still reads claude.ai or chatgpt.com This is true of Docognito and it is true of every other extension making a similar claim, because the address bar lives in the browser's own interface, not in the page an extension is allowed to redraw. A listing that promises to hide the URL, or to make the tab look like it is pointed somewhere else entirely, is describing a capability no Chrome extension has. Treat that specific claim as a reason to look elsewhere, not a reason to be impressed.
That said, none of this makes the address bar irrelevant, only outside what a browser extension can help with. The realistic use for a screen disguise is a glance, a walk-past, or a shared screen, not a situation where somebody already suspects you and is reading the browser chrome on purpose.
Try the checklist before you commit
Open the install prompt and read the permission list
Do this before the screenshots or the reviews. It is the one part of the listing Chrome itself is vouching for.
Test the toggle with a real conversation open
A single keypress that works cleanly, with no flash of the real page and no lost draft, is the difference between a tool you will actually reach for and one you will not.
Check what the listing admits it does not cover
A page that names its own limits, the address bar among them, is a more trustworthy read than one that implies it hides everything.
The decision behind picking a hiding extension
Judge any chatgpt-hiding extension against three things: does it cover the assistant you actually use, does it ask for close to nothing, and does it react to a single keypress rather than a menu. Docognito meets all three for free, with no account, and it does not pretend to hide the address bar in the process, because no Chrome extension is able to.
Try Docognito and check the permission prompt for yourself before you decide.